In this study the authors propose a novel joint detection and phase noise estimation scheme suited for severely time-dispersive channels. The authors consider single-carrier modulations combined with ...frequency domain equalisation schemes where the wireless transmission is impaired with phase noise. An iterative frequency-domain equaliser is assumed on the receiver side and the phase noise is estimated and compensated for after the equalisation step and within each iteration of the equaliser. In fact, by exploiting the Gaussianity of the equaliser output the authors are able to track the phase noise using stochastic recursive filtering techniques. These techniques share the same dynamic state-space (DSS) model. The observation equation corresponds to the measurement of the phase noise of a digitally-modulated signal affected by additive white Gaussian noise, and the dynamics equation corresponds to the Wiener–Lévy model for the phase noise. Supported on this DSS model the authors aim at estimating the unknown phase noise value given all observations up to the current time instant. In a Bayesian context this represents estimating recursively in time the filtering and the predictive distributions. From these distributions a minimum mean-squared error estimate of the phase noise is determined.
This paper introduces a conversion matrix method for linear periodically time-variant (LPTV) digital phase-locked loop (DPLL) phase noise modeling that offers precise and computationally efficient ...results to enable rapid design iteration and optimization. Unlike many previous studies, which either assume linear time-invariance (LTI) and therefore overlook phase noise aliasing effects, or solve LPTV systems with noise folding and multiple sampling rate conversions that heightens modeling and computational complexity, the proposed conversion matrix method allows the designer to represent LPTV systems using intuitive LTI-like transfer functions with excellent accuracy. Additionally, the uncorrelated upsampling method addresses the cross-correlated spectrum of cyclostationary noise sources by a simple matrix multiplication. This eliminates the need to consider the beat frequency of the upsampled noise source and the system with different sampling rates, thus improving computational efficiency. The proposed algorithm is applied to modeling a integer-<inline-formula> <tex-math notation="LaTeX">N</tex-math> </inline-formula> DPLL with time-varying proportional loop gain, and the modeling accuracy is validated with Simulink transient simulations.
This paper presents a low Phase Noise (PN) and wide tuning range Voltage-Controlled Oscillator (VCO) for V-band applications implemented with silicon-germanium (SiGe) Heterojunction Bipolar ...Transistor (HBT) switched capacitor bank and doubler. A 5-bit binary weighted capacitor bank was implemented using a novel Series-Shunt Anti-Parallel (SSAP) SiGe HBT switch, achieving 40% higher quality factor and 1.5 dB better PN than those of a conventional CMOS capacitor bank. Also, owing to low Cunit and inductance with high Q in the LC-tank, this work achieved a low PN of -105 dBc/Hz at 1 MHz offsets from 50 GHz with 31% Frequency Tuning Range (FTR), covering 47.0 to 64.3 GHz with an average frequency sensitivity of 470 MHz/V for the control voltage (Kvco), and corresponding to a figure-of-merit (FOMT ) of -190.2 dBc/Hz. To the authors' best knowledge, this is the lowest PN and Kvco of all VCOs at V-band with over 20% FTR.
In this paper, we propose two groups of recursive codes, namely the Hadamard recursive carrier interferometry (HRCI) codes and diagonal recursive carrier interferometry (DRCI) codes, to ...simultaneously reduce the peak-to-average power ratio (PAPR) and suppress the phase noises and residual carrier frequency offset (RCFO) for high-speed orthogonal frequency division multiplexing (OFDM) systems. We exploit the recursion property of the Hadamard and diagonal matrices to constitute the proposed HRCI code and DRCI code using the carrier interferometry (CI) code, and present the system model in details to spread OFDM symbols in the frequency domain. Then, we prove that both HRCI and DRCI generation matrices keep their invertibility during the recursions. As a direct result of the new code design, the phase intervals are enlarged and the signals are shifted in the time domain, thus both the PAPR and the phase noises are reduced, and the RCFO can be mitigated. Moreover, the enlarged phase intervals enable the transceiver blocks including the channel estimator, which estimate the phase noise based on the received signals, to improve the performance. Furthermore, we present the expressions for the HRCI and DRCI embedded transmitted and received signals, and derive the analytical signal-to-interference-plus-noise ratio (SINR) expressions for bit error rate (BER) performance analysis. Then, we analyze the effects of presented codes on the phase differences and provide the computational complexity analysis. Numerical simulations verify the effectiveness of our theoretical analysis of SINR. Additionally, under different parameter settings, which consider the working conditions of practical systems, we demonstrate that the presented robust HRCI and DRCI coded OFDM systems can suppress the PAPR satisfactorily and better BER performances can be achieved by the recursive CI-aided spread OFDM systems with phase noise rejection and RCFO compensation when compared with counterpart systems.
W-Band Optoelectronic Oscillator Hasanuzzaman, G. K. M.; Iezekiel, Stavros; Kanno, Atsushi
IEEE photonics technology letters,
07/2020, Letnik:
32, Številka:
13
Journal Article
We demonstrate the first W-band optoelectronic oscillator (OEO), that oscillates at 94.5 GHz with a measured single side band (SSB) phase noise of −101 dBc/Hz at an offset frequency of 10 kHz from ...the carrier. Side mode suppression of more than 65 dB has been achieved by using injection locking. This OEO has potential application as a signal source in emerging W-band applications (e.g. fiber-wireless links) and opens a path to low phase noise sources beyond 100 GHz.
This letter addresses the issue of polar coding design for bit-interleaved coded modulation (BICM) systems over the phase noise channel. Specifically, the existence of phase reference error (PRE) due ...to the imperfect phase estimation is considered. The generalized mutual information (GMI) for BICM systems with the PRE considered is first analyzed, using the exact statistical information of the received amplitude and phase, which is a foundation for the coding and decoding. Then based on the calculated average GMI per bit layer for a given PRE variance and signal-to-noise ratio (SNR), we can iteratively calculate the reliabilities of the polarized subchannels to construct polar codes. Finally, the superior performance of the phase noise-matched polar design is verified by comparing it with that of the channel-mismatched design, with 8-ary constellations used for simplicity. In addition, the comparison of the decoding performance between successive cancellation (SC) and successive cancellation list (SCL) algorithms is provided. Detailed numerical results on both frame error rate and bit error rate are given with respect to different PRE variances and SNR values. Note that this proposed scheme can be generalized to arbitrary two-dimensional high-order constellations.
This study proposes a set of mathematical formulations to model a microwave interferometric structure to stabilize a free-running oscillator. The microwave interferometric structure employed a ...carrier suppression system to lock the voltage-controlled oscillator (VCO) frequency to a high-Q resonator and clean up the phase noise spectrum. Analytical relations were derived by modeling the system's stabilization loop components with an equivalent system transfer function. This model optimized the feedback loop circuits for a reliable frequency-locked structure with suitable spectral purity using well-known linear system methods. Thus, the phase noise of an oscillator's output signal locked to a high-Q cavity resonant frequency could be predicted and optimized. Furthermore, a prototype cavity-stabilized oscillator (CSO) system with commercial components wasimplemented to validate the proposed model. The results demonstrated that approximately 40 dB phase noise reduction at 10 kHz offset frequency was obtained at X-band, exhibiting good agreement with the proposed mathematical model. Moreover, the prototype structure's feedback circuits were designed, and their performance was validated using simulation and measurement data.
In this article, the 5G New Radio (NR) physical layer evolution to support beyond 52.6 GHz communications is addressed. The performance of both OFDM based and DFT-s-OFDM based networks are evaluated ...with special emphasis on the phase noise (PN) induced distortion. It is shown that DFT-s-OFDM is more robust against PN under 5G NR Release 15 assumptions, specifically regarding the supported phase tracking reference signal (PTRS) designs. To further improve the PN compensation capabilities, the PTRS design for DFT-s-OFDM is revised, while for the OFDM waveform a novel block PTRS structure is introduced, providing similar link performance as DFT-s-OFDM with enhanced PTRS design. We demonstrate that the existing 5G NR Release 15 solutions can be extended to support deployments at 60 GHz bands with the enhanced PTRS structures. In addition, DFT-s-OFDM based downlink for user data could be considered for beyond 52.6 GHz communications to further improve system power efficiency and performance with higher order modulation and coding schemes. Finally, network link budget and cell size considerations are provided, showing that at certain bands with specific transmit power regulation, the cell size can eventually be downlink limited.
This brief overviews the development of high-performance single-core voltage-controlled oscillators (VCOs) employing a multi-LC tank over the past two decades. From the circuit-design perspective, we ...study the key breakthroughs for constantly heightening the figure-of-merit and lowering the 1/f 3 phase-noise corner, according to the noise source and transfer , narrow and wideband performance optimization, as well as one- and two-dimensional (1D/2D) tuning. We also aim to present the prospects of single-core VCOs.
The traditional interferometric synthetic aperture radar denoising methods normally try to estimate the phase fringes directly from the noisy interferogram. Since the statistics of phase noise are ...more stable than the phase corresponding to complex terrain, it could be easier to estimate the phase noise. In this article, phase noises rather than phase fringes are estimated first, and then they are subtracted from the noisy interferometric phase for denoising. The denoising convolutional neural network is introduced to estimate the phase noise and then a modified network called IPDnCNN is constructed for the problem. Based on the IPDnCNN, a novel interferometric phase noise reduction algorithm is proposed, which can reduce the phase noise while protecting fringe edges and avoid the use of filter windows. The experimental results using the simulated and real data are provided to demonstrate the effectiveness of the proposed method.
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